A SIM swap happens when someone convinces your carrier to move your phone number to a SIM or device they control. Once they receive your calls and texts, they may intercept verification codes for email, banking, and other accounts.
Does this affect you?
Use this for any U.S. mobile carrier, including Verizon, AT&T, T-Mobile, and smaller carriers that use their networks. It applies to iPhone and Android.
Recognize a SIM swap and act immediately
The clearest warning sign is sudden cell-service loss that does not behave like a normal outage.
- Watch for total loss of calls, texts, and cellular data when your bill is paid and restarting or moving locations does not fix it.
- Treat unexpected password-reset emails, two-factor codes, or new-device alerts as urgent signs someone may be using your number.
- Call your carrier immediately from another phone and say you suspect a SIM swap. Ask them to lock the account and investigate recent SIM or port activity.
- From a secure device, sign in to your most important accounts, starting with email, then banking and payment accounts, and change passwords.
- Check bank and card accounts for unauthorized transactions or new payees.
Protect your phone number before it happens
Carrier account settings make unauthorized transfers harder.
- Add a mobile account PIN, port-out PIN, or account passcode. This is separate from your phone unlock code and is required for number transfers or account changes.
- Ask the carrier about stronger protections such as in-person ID requirements, callback verification, transfer locks, or account change locks.
- Move important accounts away from SMS codes where possible. Use an authenticator app, passkey, or physical security key instead.
- Limit public personal information such as full birthday, address, and family details that scammers can use to impersonate you.
- Consider freezing credit with Equifax, Experian, and TransUnion because SIM swaps are often a step toward broader identity theft.
More control
SMS codes depend on number control
Text-message two-factor assumes you are the only person receiving texts to your number. A SIM swap breaks that assumption even if the password was strong.
The carrier PIN is high value
Many SIM swaps succeed through social engineering of carrier support. A separate port-out or account PIN gives the representative a stronger check before approving changes.
Sources
- Federal Communications Commission – SIM Swapping (2025)
- FBI Internet Crime Complaint Center IC3 – SIM Swapping Public Service Announcement (2025)
- CTIA – Protecting Your Mobile Account (2025)